Sodium Hydroxide → tert-butyl N-[4-[3-[2-[(2-hydroxyacetyl)amino]-6-methyl-4-nitrophenyl]phenyl]sulfonyl-5-methylsulfanylthiophene-2-carboximidoyl]carbamate

Participants

Reaction Steps

To a solution of {[4-(6′-amino-2′-methyl-4′-nitro-biphenyl-3-sulfonyl)-5-methylsulfanyl-thiophen-2-yl]-imino-methyl}-carbamic acid tert-butyl ester (216 mg, 0.384 mmol, as prepared in Example 295, step h) in DCM (2 mL) was added DIEA (212 μL, 1.15 mmol) and acetoxyacetyl chloride (54 mL, 0.5 mmol). The solution was stirred at rt for 3 hr. The reaction mixture was diluted with EtOAc and washed with saturated NaHCO3, water, and brine. The organic layer was dried over MgSO4, filtered, and concentrated in vacuo to provide 256 mg of a crude oil that was used without further purification. ESI-MS (m/z): Calcd. for C28H30N4O9S3: 663.1 (M+H); found: 662.7, 563.0 (M−Boc). To a solution of the crude intermediate obtained above in MeOH (2.5 mL) was added 1 N NaOH (2.5 mL) and the mixture was stirred at rt for 45 min at which time TLC was consistent with complete conversion. The reaction mixture was neutralized with acetic acid, concentrated in vacuo, and the residue partitioned between EtOAc and saturated NaHCO3. The organic layer was washed with water and brine, dried over MgSO4, filtered, and concentrated in vacuo to give 220 mg (92%, crude yield over two steps) of the title compound which was used without further purification. ESI-MS (m/z): Calcd. for C26H28N4O8S3: 621.1 (M+H); found: 620.7, 521.0 (M−Boc).

Provenance & Evidence